scholarly journals Intracellular regulators of neuronal sprouting: calmodulin-binding proteins of nerve growth cones.

1985 ◽  
Vol 101 (3) ◽  
pp. 1153-1160 ◽  
Author(s):  
C Hyman ◽  
K H Pfenninger
Keyword(s):  
Growth Cone ◽  
Binding Proteins ◽  
Growth Cones ◽  
Binding Studies ◽  
Nerve Growth ◽  
Calcium Dependent ◽  
Calmodulin Binding ◽  
Nerve Growth Cone ◽  
The Individual ◽  
Neuronal Sprouting

The focus of this study is a quantitative biochemical analysis of the calcium-dependent interactions of calmodulin with a nerve growth cone preparation from fetal rat brain (Pfenninger, K. H., L. Ellis, M. P. Johnson, L. B. Freidman, and S. Somlo, 1983, Cell 35:573-584). The presence of calmodulin as an integral component of this preparation is demonstrated, and quantitative binding studies are presented. The binding of 125I-calmodulin to nerve growth cone material is shown to be highly specific, calcium dependent, and saturable at nanomolar calmodulin concentrations. Additionally, the growth cones' binding components appear to be membrane proteins. The individual molecular mass species of growth cone proteins displaying calcium-dependent calmodulin binding are also detailed and presented in comparison with those of synaptosomes. This analysis reveals differences between the calmodulin binding proteins of the growth cone preparation and the synaptosome fraction, suggesting the presence in growth cones of a specialized set of components which may be involved in regulatory mechanisms controlling neuritic sprouting.

scholarly journals Radixin Is Involved in Lamellipodial Stability during Nerve Growth Cone Motility

1999 ◽  
Vol 10 (5) ◽  
pp. 1511-1520 ◽  
Author(s):  
Leslie Castelo ◽  
Daniel G. Jay
Keyword(s):  
Growth Cone ◽  
Critical Role ◽  
Leading Edge ◽  
Growth Cones ◽  
Forward Movement ◽  
Nerve Growth ◽  
Nerve Growth Cone

Immunocytochemistry and in vitro studies have suggested that the ERM (ezrin-radixin-moesin) protein, radixin, may have a role in nerve growth cone motility. We tested the in situ role of radixin in chick dorsal root ganglion growth cones by observing the effects of its localized and acute inactivation. Microscale chromophore-assisted laser inactivation (micro-CALI) of radixin in growth cones causes a 30% reduction of lamellipodial area within the irradiated region whereas all control treatments did not affect lamellipodia. Micro-CALI of radixin targeted to the middle of the leading edge often split growth cones to form two smaller growth cones during continued forward movement (>80%). These findings suggest a critical role for radixin in growth cone lamellipodia that is similar to ezrin function in pseudopodia of transformed fibroblasts. They are consistent with radixin linking actin filaments to each other or to the membrane during motility.

Nerve growth cone migration onto Schwann cells involves the calcium-dependent adhesion molecule, N-cadherin

1990 ◽  
Vol 138 (2) ◽  
pp. 430-442 ◽  
Author(s):  
Paul C. Letourneau ◽  
Terri A. Shattuck ◽  
Florence K. Roche ◽  
Masatoshi Takeichi ◽  
Vance Lemmon
Keyword(s):  
Schwann Cells ◽  
Adhesion Molecule ◽  
Growth Cone ◽  
Nerve Growth ◽  
Calcium Dependent ◽  
Nerve Growth Cone

scholarly journals Plasmalemmal insertion and modification of sodium channels at the nerve growth cone

1992 ◽  
Vol 12 (8) ◽  
pp. 2948-2959 ◽  
Author(s):  
MR Wood ◽  
J DeBin ◽  
GR Strichartz ◽  
KH Pfenninger
Keyword(s):  
Sodium Channels ◽  
Growth Cone ◽  
Nerve Growth ◽  
Nerve Growth Cone

scholarly journals Calmodulin-dependent activation and inactivation of anoctamin calcium-gated chloride channels

2013 ◽  
Vol 142 (4) ◽  
pp. 381-404 ◽  
Author(s):  
Kerstin Vocke ◽  
Kristin Dauner ◽  
Anne Hahn ◽  
Anne Ulbrich ◽  
Jana Broecker ◽  
...  
Keyword(s):  
Splice Variant ◽  
Chloride Channels ◽  
Cell Types ◽  
Binding Motif ◽  
Binding Studies ◽  
Channel Activation ◽  
Calcium Dependent ◽  
Calmodulin Binding ◽  
Dependent Inactivation ◽  
Cl Channels

Calcium-dependent chloride channels serve critical functions in diverse biological systems. Driven by cellular calcium signals, the channels codetermine excitatory processes and promote solute transport. The anoctamin (ANO) family of membrane proteins encodes three calcium-activated chloride channels, named ANO 1 (also TMEM16A), ANO 2 (also TMEM16B), and ANO 6 (also TMEM16F). Here we examined how ANO 1 and ANO 2 interact with Ca2+/calmodulin using nonstationary current analysis during channel activation. We identified a putative calmodulin-binding domain in the N-terminal region of the channel proteins that is involved in channel activation. Binding studies with peptides indicated that this domain, a regulatory calmodulin-binding motif (RCBM), provides two distinct modes of interaction with Ca2+/calmodulin, one at submicromolar Ca2+ concentrations and one in the micromolar Ca2+ range. Functional, structural, and pharmacological data support the concept that calmodulin serves as a calcium sensor that is stably associated with the RCBM domain and regulates the activation of ANO 1 and ANO 2 channels. Moreover, the predominant splice variant of ANO 2 in the brain exhibits Ca2+/calmodulin-dependent inactivation, a loss of channel activity within 30 s. This property may curtail ANO 2 activity during persistent Ca2+ signals in neurons. Mutagenesis data indicated that the RCBM domain is also involved in ANO 2 inactivation, and that inactivation is suppressed in the retinal ANO 2 splice variant. These results advance the understanding of Ca2+ regulation in anoctamin Cl− channels and its significance for the physiological function that anoctamin channels subserve in neurons and other cell types.

scholarly journals c-src gene product in developing rat brain is enriched in nerve growth cone membranes.

1988 ◽  
Vol 85 (14) ◽  
pp. 5001-5005 ◽  
Author(s):  
P. F. Maness ◽  
M. Aubry ◽  
C. G. Shores ◽  
L. Frame ◽  
K. H. Pfenninger
Keyword(s):  
Rat Brain ◽  
Gene Product ◽  
Growth Cone ◽  
Nerve Growth ◽  
Src Gene ◽  
Nerve Growth Cone ◽  
Developing Rat

scholarly journals Calmodulin and Calmodulin Binding Proteins in Dictyostelium: A Primer

2020 ◽  
Vol 21 (4) ◽  
pp. 1210
Author(s):  
Danton H. O’Day ◽  
Ryan J. Taylor ◽  
Michael A. Myre
Keyword(s):  
Conformational Changes ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Regulatory Protein ◽  
Model Organism ◽  
Ion Binding ◽  
Calcium Dependent ◽  
Calmodulin Binding ◽  
Human Counterpart ◽  
Ef Hands

Dictyostelium discoideum is gaining increasing attention as a model organism for the study of calcium binding and calmodulin function in basic biological events as well as human diseases. After a short overview of calcium-binding proteins, the structure of Dictyostelium calmodulin and the conformational changes effected by calcium ion binding to its four EF hands are compared to its human counterpart, emphasizing the highly conserved nature of this central regulatory protein. The calcium-dependent and -independent motifs involved in calmodulin binding to target proteins are discussed with examples of the diversity of calmodulin binding proteins that have been studied in this amoebozoan. The methods used to identify and characterize calmodulin binding proteins is covered followed by the ways Dictyostelium is currently being used as a system to study several neurodegenerative diseases and how it could serve as a model for studying calmodulinopathies such as those associated with specific types of heart arrythmia. Because of its rapid developmental cycles, its genetic tractability, and a richly endowed stock center, Dictyostelium is in a position to become a leader in the field of calmodulin research.

Tissue distribution of rat S100 alpha and S100 beta and S100-binding proteins

1987 ◽  
Vol 252 (3) ◽  
pp. C285-C289 ◽  
Author(s):  
D. B. Zimmer ◽  
L. J. Van Eldik
Keyword(s):  
Calcium Binding ◽  
Binding Proteins ◽  
Physiological Role ◽  
Rat Tissues ◽  
Differential Distribution ◽  
Binding Profile ◽  
Calmodulin Binding ◽  
The Individual ◽  
Intracellular Targets

To understand the physiological role of the calcium-binding proteins S100 alpha and S100 beta, it is necessary to determine the distribution of these proteins and detect their intracellular targets in various tissues. The distribution of immunoreactive S100 alpha and S100 beta in various rat tissues was examined by radioimmunoassay. All tissues examined contained detectable S100, but the S100 beta/S100 alpha ratio in each tissue differed. Brain, adipose, and testes contained 18- to 40-fold more S100 beta than S100 alpha; skin and liver contained approximately equivalent amounts and kidney, spleen, and heart contained 8- to 75-fold more S100 alpha than S100 beta. Analysis of S100-binding proteins by gel overlay showed that each tissue possessed its own complement of binding proteins. The S100 beta-binding profile was indistinguishable from the S100 alpha-binding profile and both of these profiles were distinct from the calmodulin-binding profile. These observations suggest that the differential distribution and quantity of the individual S100 polypeptides and their binding proteins in various tissues may be important factors in determining S100 function.

scholarly journals BMP gradients steer nerve growth cones by a balancing act of LIM kinase and Slingshot phosphatase on ADF/cofilin

2007 ◽  
Vol 178 (1) ◽  
pp. 107-119 ◽  
Author(s):  
Zhexing Wen ◽  
Liang Han ◽  
James R. Bamburg ◽  
Sangwoo Shim ◽  
Guo-li Ming ◽  
...  
Keyword(s):  
Growth Cone ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Growth Cones ◽  
Actin Dynamics ◽  
Lim Kinase ◽  
Nerve Growth ◽  
Nerve Growth Cones ◽  
Transient Receptor ◽  
Calcineurin Phosphatase

Bone morphogenic proteins (BMPs) are involved in axon pathfinding, but how they guide growth cones remains elusive. In this study, we report that a BMP7 gradient elicits bidirectional turning responses from nerve growth cones by acting through LIM kinase (LIMK) and Slingshot (SSH) phosphatase to regulate actin-depolymerizing factor (ADF)/cofilin-mediated actin dynamics. Xenopus laevis growth cones from 4–8-h cultured neurons are attracted to BMP7 gradients but become repelled by BMP7 after overnight culture. The attraction and repulsion are mediated by LIMK and SSH, respectively, which oppositely regulate the phosphorylation-dependent asymmetric activity of ADF/cofilin to control the actin dynamics and growth cone steering. The attraction to repulsion switching requires the expression of a transient receptor potential (TRP) channel TRPC1 and involves Ca2+ signaling through calcineurin phosphatase for SSH activation and growth cone repulsion. Together, we show that spatial regulation of ADF/cofilin activity controls the directional responses of the growth cone to BMP7, and Ca2+ influx through TRPC tilts the LIMK-SSH balance toward SSH-mediated repulsion.

scholarly journals Characterization of the turning response of dorsal root neurites toward nerve growth factor.

1980 ◽  
Vol 87 (3) ◽  
pp. 546-554 ◽  
Author(s):  
R W Gundersen ◽  
J N Barrett
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Growth Cone ◽  
Dorsal Root ◽  
Growth Cones ◽  
Individual Growth ◽  
Ionophore A23187 ◽  
Nerve Growth ◽  
Neurite Initiation ◽  
Turning Response

This study reports that chick dorsal root ganglion neurites undergo a rapid (20 min) reorientation of their direction of growth in response to nerve growth factor (NGF) concentration gradients in vitro. Dorsal root ganglia from chick embryos were explanted onto a collagen-poly-L-lysine substrate. After 24-48 h in culture, NGF gradients were applied to individual growth cones via a micropipette containing 50 biological units NGF/ml. The growth cones turned and grew toward these NGF sources. This turning response was not caused by the trophic effects of NGF on neurite initiation, survival, or growth rate. Dorsal root neurites also grew toward sources of mono- and dibutyryl cyclic adenosine monophosphate (dB cAMP), cyclic guanosine monophosphate (cGMP), and elevated calcium in the presence of the calcium ionophore A23187. These results are consistent with the hypothesis that intracellular levels of cAMP and /or cGMP and calcium may play a role in the turning response of dorsal root neurites toward NGF, but do not establish a causal relationship between the mechanisms of action of NGF, cyclic nucleotides and calcium. Total growth cone adherence to the substrate was measured using a timed microjet of perfusion medium. NGF increased the adherence of growth cones to the substrate, but caffeine and dB cAMP which also elicit the positive turning response, decreased growth cone adherence. Calcium, which did not elicit the positive turning response, produced a greater growth cone adherence to the substrate than that observed with NGF. Although these results do not rule out a role of adhesion changes in axonal turning to NGF, they show that a general increase in adherence does not correlate well with the rapid turning response observed in this study.

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